Multizone laundry iron and method for the thermal regulation of the hot part

ABSTRACT

Electric steam iron having a hot part (1) composed of a sole (7) and a steam chamber (4), the sole having a portion situated under the steam chamber, and the hot part (1) of the iron being subdivided into at least two thermal zones. A plurality of heating elements are each disposed to heat a respective one of the thermal zones and a plurality of regulation organs are each associated with a respective one of the heating elements. The at least two thermal zones include a first thermal zone (A) having at least one surface corresponding substantially to the steam chamber (4) and a second thermal zone (B) having at least one surface corresponding substantially to the portion of the sole situated under the steam chamber, the first thermal zone (A) and the second thermal zone (B) being in thermal communication with one another. The heating element which is disposed to heat the first thermal zone is arranged to at least partially heat the second thermal zone.

TECHNICAL FIELD

The present invention relates to the general technical field ofappliances conceived for the care of a textile article, such as aclothing article, by subjecting it to the combined action of a thermaltreatment, a mechanical pressing treatment and a steam treatment.

The present invention concerns an electric steam iron comprising a hotpart composed of a sole and a steam chamber, said hot part of the ironbeing subdivided into at least two thermal zones, each of them beingprovided with a heating element and associated with a control organ.

PRIOR ART

In pressing irons of the prior art, the thermal energy transmitted tothe pressing sole is conventionally furnished by heating elements suchas tubular heating elements, or even by heating elements of the flattype including a resistive strip. In this latter case the resistivestrip forms a heating circuit defining on the pressing sole a heatingzone, said strip being inserted between two electrically insulatingfilms adhering to one another and also maintaining the resistive stripin place. In one case or the other, it is important to maintain orcontrol the temperature of the pressing sole below an assignedtemperature. To this end, it is conventional to use regulation means ortemperature sensors, for example a thermostat, disposed in the pressingiron in thermal communication with the heating element. As a generalrule the thermostat or any other temperature regulation or control organis disposed in thermal communication with the heating element in apreviously selected zone and often as close as possible to the zoneidentified as being the hottest at the level of the sole. In effect, itis in order to be careful to avoid or at least limit the conventionalproblem of exceeding frequently occurring in pressing irons.

Such a phenomenon is produced when the temperature control or regulationorgan only records or controls a thermal image of the heating elementwhich is shifted in time and/or in space. This occurs when thethermostat is for example situated in a zone which is too far from theheating element, in such a manner that the thermostat is triggered atthe correct assigned temperature but too late, at least a portion of thepressing sole being already at a temperature greater than the assignedtemperature. In order to remedy at least in part this conventionalphenomenon of thermal disfunctioning, it is consequently well-known tosystematically fix the temperature control or regulation organs in thezone of the heating element known to be the hottest.

This solution presents however inconveniences. On the one hand,determination of the hottest zone of a heating element, or even of apressing iron sole is not always sufficiently precise and can even varyfrom one appliance to another. On the other hand, the necessity ofsystematically placing the temperature control organ in the hottest zoneof the appliance constitutes an additional fabrication constraintlimiting the possibilities of arranging and mounting the other organs ofthe appliance. This solution is that much more constraining, notably inpressing irons, when the volume available for mounting the differentorgans necessary for the functioning of the appliance is limited. Thisconstraint thus constitutes a negative factor with regard to the freedomof design and arrangement of the organs in the available volume.

French Patent Application No. 2,691,723 discloses a household applianceparticularly a pressing iron in which control of the temperature isimproved. For this it comprises a heating element including at least oneresistive strip forming a heating circuit delimiting a heating surface,and a temperature control or regulation organ disposed in thermalcommunication with said heating element, said heating surface comprisingat least one local overheating zone opposite which is disposed thetemperature control or regulation organ.

Nevertheless, despite the advance provided by such an arrangement andwith the objective of offering an operator the best possible utilizationcomfort of a pressing iron for a further improved pressing, it has beendetermined that control of the temperature of the sole could be furtherimproved.

In effect, in most of the appliances known in the prior art, includingin that described in the above-cited application, the regulation/heatingcircuit is unique. Consequently, the associated regulation organ canhave only a partial image of the temperature of the iron sole. It is aquestion of the temperature existing at the precise location where thisregulation organ is fixed. This organ thus activates the heating elementwhen the temperature of the point on which it is fixed passes below anassigned value, without taking into account the temperature differenceswhich exist between different points of the sole.

In any event, even if one were to resolve this problem, for example byplacing several temperature probes at different points of the sole, andby averaging the values, the heating element being unique, one will notdispose heating means in a selective fashion certain zones of this sole.To the contrary, by resupplying the heating element, on will supplycalories to the heating element, without taking into account the realtemperature state of each zone. One will thus maintain, even aggravate,the temperature distortion state in which the sole is found.

There are equally known irons whose sole is composed of two thermalzones each composed of a heating element. The document GB-2 006 835describes such an iron, composed of a frontal zone and a rear zone. Thisconfiguration aims at compensating the substantial thermal lossesundergone by the frontal region, in general highly solicited.

Moreover, an having a hot part composed of a sole and a steam chamber,the sole and the steam chamber each being provided with a heatingelement iron is known from the document U.S. Pat. No. 3,110,975.

In the case of steam irons where a heating element is associated withthe steam chamber (in general only one serving at the same time tofurnish heat energy for the vaporization of water and to heat the sole),applicant has noted and confirmed by thermographs that the part of thesole plate located under the steam chamber is substantially colder thanthe rest of the surface of the sole, in particular during thevaporization operation. This situation is troublesome since it isdesired in general that the surface of the sole of the iron attain itsoptimum temperature at the moment when the steam is emitted.

SUMMARY OF THE INVENTION

The object of the invention is thus to provide a steam iron such thatone can manage in a selective fashion the temperature of severaldifferent zones of the hot part of the iron either of the sole and/or ofthe steam chamber. One can thus, by construction, by disposing as manythermal regulation organs and by managing in an adapted manner theseregulations, eliminate or attenuate the cold zone situated below thesteam chamber. One will thus achieve a sole capable of vaporizing waterwhile maintaining a temperature at all points adapted to the fabric. Inaddition, one can optimize the efficiency of the steam chamber andprovide a pressing iron capable of vaporizing large quantities of water(greater than 30 grams/minute) and steam iron synthetic fabrics forwhich the temperature of the sole in contact with the linen must remainaround 100° C.

Another object of the invention consists in proposing a pressing ironwhose sole comprises several temperature zones capable of being managedin an independent manner in order to be able to be situated at differenttemperature levels with respect to one another.

These objects are achieved according to the invention concerning anelectric steam pressing iron comprising a hot part composed of a soleand a steam chamber, said hot part of the iron being subdivided into atleast two thermal zones A, B, C, each of them being provided with aheating element and associated with a regulation organ characterized onthe one hand in that the first zone A comprises at least one surfacecorresponding substantially to the steam chamber and on the other handin that a second zone B comprises at least one surface correspondingsubstantially to the portion of the sole situated under the chamber.

The thermal losses due to vaporization are thus compensated by theheating element disposed between the steam chamber and the sole. Thiselement permits to avoid the creation of a cold zone under the steamchamber in the case where this latter absorbs a substantial quantity ofthermal energy.

According to an advantageous form of construction of the invention, theregulation element associated with zone B is provided to activate theheating element associated with zone B in particular during steamgeneration. Since the risk of appearance of the cold zone is less at themoment of vaporization, one suppresses the risk by furnishing additionalthermal energy at the most critical moment.

According to another advantageous form of construction of the inventionat least one of said heating elements is associated with a mechanicaland/or electronic vaporization control. Preferably, this heating elementis that corresponding to zone B situated under the steam chamber. Thismanner of control assures that the thermal energy of the sole will notbe absorbed by the vaporization process. The user does not have to bepreoccupied with the temperature of the sole, the heating beingcontrolled automatically during the steam generation.

According to another advantageous form of construction of the invention,the first zone A equally comprises at least one portion of the surfacecorresponding substantially to the portion of the sole not covered bysaid steam chamber. One can in this manner assure the temperaturesetting of the portion of the sole situated for example at the rear ofthe steam chamber, without necessarily continually using the secondheating element.

According to another advantageous form of construction of the inventionthe hot part comprises a third thermal zone C provided with a heatingelement and associated with a regulation organ, said zone being disposedpreferably in proximity to the peripheral edge of the sole. One can thuscreate a thermal map of the sole according to a multitude ofpossibilities.

According to another advantageous form of construction of the invention,the second heating element is substantially flat. It is then easy tointegrate it into the reduced space located between the steam chamberand the sole.

The objects of the invention are also achieved due to a method ofthermal regulation for an electric steam pressing iron, in which theheating element is regulated in a manner to avoid the formation of acold zone at the level of the sole, notably during steam generation.

According to a preferred variant of the thermal regulation method for anelectric steam pressing iron, the setting of the temperature of zone Ais assured by a first heating element and that of the zone B at the sametime by the first heating element and by a second distinct heatingelement. The second heating elements thus serves as a supplementalheating means.

According to another preferred variant of the thermal regulation methodfor an electric steam pressing iron, the setting of the temperature ofzone A is assured by a first distinct heating element and that of thezone B by a second distinct heating element. This manner of regulationpermits a great flexibility at the level of the management of thethermal map of the sole.

The present invention equally concerns characteristics which will appearduring the course of the description which follows, and which should beconsidered individually or according to all of their possible technicalcombinations.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention will appear moreclearly in the light of the description and the drawings which follow,illustrating, by way of nonlimiting examples, embodiments of theinvention. Thus, reference is made to FIGS. 1 to 3 where:

FIG. 1 is a view in cross section of the hot part of a pressing ironaccording to the invention,

FIG. 2 is a partial bottom view of a pressing iron according to FIG. 1,

FIG. 3 is a partial bottom view of a pressing iron according to amodified embodiment of the thermal zones of the hot part.

BEST MANNER OF ACHIEVING THE INVENTION

According to a first preferred form of construction of the invention, asteam chamber 4 is formed in the hot part 1 of the iron. A first heatingelement 2, preferably tubular, is inserted by overmolding, by fitting ina groove, or by any other means on a support 3. This support 3 is mostoften made of molded aluminum, but it is obvious that this material canbe replaced by any other material whose conductivity characteristics areadvantageous.

This support delimits in addition steam chamber 4. This chambercommunicates in a conventional manner with a reservoir (not shown)supplying the water necessary for the production of steam. According tothe form of construction, it can be a matter of a reservoir integratedinto the iron, or a reservoir of the external type, both of these typesbeing known. The steam chamber can equally be connected to an externalsteam generator equally of a known type.

A regulation organ 8 or thermostat cooperates thermally with steamchamber 4. This heating element 2 is supplied by the intermediary of anelectric supply source 9 in a manner to furnish the heat energynecessary on the one hand for the vaporization of water and on the otherhand for the heating of the sole. This first heating element 2 acts inparticular on a zone "A" of the hot part corresponding substantially tothe steam chamber and possibly to another portion of the sole, notcovered by the steam chamber (FIGS. 1 and 2).

In the embodiment examples described, the rear portion of the sole notcovered by the steam chamber, is designated A when it is brought to itstemperature by the same heating element as zone A, and A' when itpossesses a distinct heating element.

Moreover and in a completely independent manner, hot part 1 comprises atits lower part another heating element 11 preferably flat, defining azone "B" corresponding substantially to the portion of the sole situatedunder chamber 4. The flat heating element 11 is housed in a recess 10arranged between support 3 and sole 7. According to an advantageous formof construction of the invention, the heating element of zone "B" isintended to compensate the "thermal losses" provoked by thevaporization, tending to give rise to an at least partial cooling inthis zone.

Flat hot part 1 is controlled by regulation organ or thermostat 12independently of the above-cited thermostat 8 of steam chamber 4. Theregulation can equally be effectuated electronically. According tovariations envisioned, the regulation can permit the heating of zone "B"in a manner entirely independent of zone "A", or even in complement ofheating element when this is necessary, notably during steam generation.According to another variant, a complementary regulation organ 8a,disposed at the level of part "A" of the sole can complete theregulation of zone "A", for example in order to avoid exceeding certaingiven temperature limits.

Flat heating element 11 is preferably flexible and made according to aconventional technique. It includes at least one resistive strip made ofany material which is a good conductor of heat, such as aluminum,copper, constant an, for example said strip forming a heating circuitwhose exterior envelope interiorly delimits a heating surface. Theresistive strip is in a known manner either inserted between twoelectrical insulating films adherent to one another for example bycementing and maintaining the strip in place. The electrical insulatingfilms can be selected from among all known insulating materials such asPVC, polyester, polyamide, silicone, micanite, etc.

In the preferred application envisioned, the heating element issubstantially flat. One can however utilize a traditional heatingelement, for example of the tubular type.

The heating element represented is intended to be integrated into apressing iron by cementing between the pressing sole itself and an uppersupport plate.

According to this embodiment example, hot part 1 of the iron issubdivided in fact into two zones "A" and "B", in a preferred mannermechanically joined together to one another. The arrangement is providedso that the different zones are preferably substantially thermallyindependent: zone "B" being provided with a distinct heating element 11which belongs to it, associated with a regulation organ 12 independentof regulation organ 8 of heating element 2 of zone "A". It is thenpossible to manage in a selective fashion the temperature of said zones"A" and "B" independently of one another, as a function of a desiredthermal cartography of the sole.

In the case of the form of construction shown in FIG. 1, it isadvantageous that the two defined thermal zones not be isolated from oneanother in order to facilitate the thermal transfers. This configurationpermits utilization of flat heating element 11 solely as supplement.Thus, in such a case, the heating element under the steam chamber can beactivated only during steam generation in order to avoid the creation ofthe cold zone previously described. Outside of the steam generationperiod, the heating element associated with the steam chamber thenequally assures heating of all of the sole.

Control of heating element 11 can equally be associated with amechanical and/or electronic steam generation control.

According to another variant, zones "A" and "B" are substantiallyinsulated from one another; establishment of the temperature in zone "B"can then only be achieved by heating element 11 associated with thiszone.

Starting from these basic examples, all variations can be enumerated.

In the same manner, according to the possible variations, heatingelement 11 disposed under chamber 4 is maintained at a fixedtemperature, or is controlled by a regulation organ 12 such as describedpreviously.

According to another variation, one can equally provide that the heatingelement 11 disposed under chamber 4 and/or heating element 2 of thesteam chamber are placed under voltage in an alternating manner by theintermediary of a device (not shown) for detecting the presence of thehand of the operator, in a manner to assure their operation only duringa period of work, to the exclusion of rest periods in the pressing cycleadopted.

According to another variation of the invention, heating element 2 ofsteam chamber 4 is regulated either as a function of a fixedinstructions, or as a function of a variable instruction determined bythe operator, or linked to a physical quantity.

According to another variation of the invention, heating element 11situated under chamber 4 is a flat heating element while heating element2 situated in steam chamber 4 is a tubular heating element.

In another form of construction represented in FIG. 3, heating element 2is always composed of a first zone A corresponding substantially tosteam chamber 4, but sole 7 is composed of two thermal zones "A'" and"B" situated respectively behind and in front of said sole 7 to which isadded a third thermal zone "C" disposed in proximity to its peripheraledge 22, each of said zones "A", "A'", "B" and "C" being raised intemperature by the intermediary of distinct heating elements 11, 13, 20and 2, controlled independently of one another by respective regulationorgans 12, 14, 21, 8, as a function of the desired temperaturecartography of the sole.

It is thus that the different thermal zones "A'" , "B" and/or "C" of theheating circuit of sole 7 comprise flat heating elements 11, 13, 20attached on sole 7, either directly or by the intermediary of anattached plate.

The different thermal zones "A'", "B" and/or "C" of the heating circuitof sole 7 can equally comprise tubular heating elements (not shown)attached on sole 7 either directly or by the intermediary of an attachedplate.

The different thermal zones "A", "A'", "B" and/or "C" of the heatingcircuit of the sole can also comprise flat heating elements 11, 13and/or tubular.

Advantageously regulation organs 12, 14, 21, 8 of the different heatingelements are connected to control means arranged to permit a programmingof the temperature gradients chosen as a function of the different zonesof sole 7 in order to modulate the pressing temperature depending on thefabrics.

The means employed by the invention and which have just been describedhereabove can permit on the one hand avoiding the cold zone situatedunder the steam chamber, and on the other hand obtaining at the sametime a perfectly uniform temperature of the pressing iron sole and arigorous control of intentionally different temperature zones, forexample to achieve a front attach zone which is hotter than a rear zone.

POSSIBILITIES OF INDUSTRIAL APPLICATION

The present invention finds its application in the construction of anelectric steam pressing iron comprising a hot part 1 composed of a sole7 and a steam chamber 4, said hot part 1 of the iron being subdividedinto at least two thermal zones A, B, C, each of them being equippedwith a heating element 11, 13, 20 and associated with a regulation organ12, 14, 21.

We claim:
 1. Electric steam iron comprising: a hot part (1) composed ofa sole (7) and a steam chamber (4), said sole having a portion situatedunder said steam chamber, said hot part (1) of the iron being subdividedinto at least two thermal zones (A, A', B, C); a plurality of heatingelements (2, 13, 11, 20) each disposed to heat a respective one of thethermal zones; and a plurality of regulation organs each associated witha respective one of said heating elements (8, 14, 12, 21), the at leasttwo thermal zones including a first thermal zone (A) comprising at leastone surface corresponding substantially to the steam chamber (4) and asecond thermal zone (B) comprising at least one surface correspondingsubstantially to the portion of said sole situated under said steamchamber, the first thermal zone (A) and the second thermal zone (B)being in thermal communication with one another, wherein said heatingelement which is disposed to heat the first thermal zone is arranged toat least partially heat the second thermal zone.
 2. Iron according toclaim 1, in which the regulation organ (12) associated with the heatingelement disposed to heat the second thermal zone (B) is provided toactivate that heating element during steam generation.
 3. Iron accordingto claim 1, in which at least one of said heating elements is associatedwith at least one of a mechanical and electronic steam generationcontrol.
 4. Iron according to claim 3, in which said at least one ofsaid heating elements is that corresponding to said second thermal zone.5. Iron according to claim 1, wherein a portion of said sole is notsituated under said steam chamber and the first zone (A) comprisesequally at least one surface portion corresponding substantially to theportion of the sole (7) not situated under said steam chamber (4). 6.Iron according to claim 1, wherein said sole has a peripheral edge, andsaid at least two thermal zones further comprise a third thermal zone(C) at which one of said plurality of heating elements is disposed, saidthird thermal zone being disposed in proximity to the peripheral edge ofsaid sole.
 7. Iron according to claim 1, wherein at least one of theheating elements (2, 11, 20) is susceptible to being turned on inalternation by the intermediary of a device for detecting the presenceof the hand of the operator, in a manner to assure operation of said oneof the heating elements only in a work period to the exclusion of restperiods of the pressing cycle adopted.
 8. Iron according to claim 1,wherein the regulation organs (12, 14, 21, 8) of the different heatingelements are connected to control means able to permit a programming ofthe temperature gradients chosen as a function of the different zones ofthe sole (7) in order to modulate the pressing temperature according tothe fabrics.
 9. Iron according to claim 1, wherein each of said heatingelements is constituted by a resistive part.
 10. Iron according to claim1, wherein each of said heating elements is one of a flat heatingelement and a tubular heating element.
 11. Iron according to claim 1,wherein said heating element which is disposed to heat said secondthermal zone is substantially flat.
 12. Thermal regulation method forregulating the electric steam iron defined in claim 1, comprisingheating the first thermal zone by said heating element disposed to heatthe first thermal zone, and heating the second thermal zone by saidheating elements disposed to heat the first and second thermal zones.13. Thermal regulation method according to claim 12 further comprisingeffecting thermal regulation in each of said thermal zones under controlof only one respective one of said regulation organs.
 14. Thermalregulation method according to claim 12 further comprising regulatingsaid heating elements as a function of a fixed instruction.
 15. Thermalregulation method according to claim 12 further comprising regulatingsaid heating elements as a function of a variable instruction determinedby the operator.
 16. Thermal regulation method according to claim 12further comprising regulating said heating elements as a function whichis linked to a physical quantity.